Intel IQ80219 PCIX Initialization Summary, User Defined Switches, Hardware Reference Section

Intel® IQ80219 General Purpose PCI Processor Evaluation Platform

Hardware Reference Section

3.10.2PCIX Initialization Summary

Figure 16 shows a routing guidance on how PCI-X mode is determined/implemented on the secondary side of the PCI-X bridge. The 80219, GbE device, and the PCI-X expansion slot all reside on this bus.

Figure 16. PCI-X Routing Diagram on Secondary PCI-X Bridge

Switch	Switch	Switch
S8E1-4	S7E1-8	S7E1-6	S7E1-7

Sel 100		Enable		Selection
				33 MHz	66 MHz	100 MHz	133 MHz
PCI-X					Clock
Bridge			Multiplier/Bufferr
		PCI-X Clock
		PCIXCAP
		M66EN Signal
		S_DEVSEL
	Initialization Signals	S_TRDY
		S_FRAME
		S_IRDY
		S_STOP

Switch

S8E2-1 S8E2-2

PCIXCAP

OSC

Switch

S8E2-4

M66EN

SPCI-X Slot

Intel® 80219

General

Purpose

PCI

Processor

82544

Gigabit Ethernet

B2840-01

3.10.2.1User Defined Switches

User can set the PCIXCAP signal to force one of the following modes:

• PCI-X 100/133 • PCI-X 66 • PCI

The IQ80219 platform is by default set to operate this bus in PCI-X 66 MHz mode. The loading on the secondary PCI-X bus may result in marginal operation when speed is greater than that.

When an expansion card is placed on the PCI-X expansion slot, the mode is based on the least capable device on the bus. For example, when the bus is forced to be PCI-X 66 capable and then places a PCI 66 card in the expansion slot, then the bus is configured as PCI 66.

Important: The clock selection is manually configured. Pay close attention to setting this up correctly.

Important: All settings must be done prior to power-up/reset.

3.10.2.2PCI-X Bridge Initialization Signals

The On-board PCI-X bridge samples the PCIXCAP, SEL100, and M66EN signals to drive/indicate the correct mode to the secondary bus devices. The 80219 uses these signals to set its internal PLs, providing correct frequency to the Intel XScale® core, as well as internal, peripheral, and DDR buses.

Board Manual 53